RFC 7533

Administration Protocol for Federated File Systems

Internet Engineering Task Force (IETF) J. Lentini
Request for Comments: 7533 NetApp
Category: Standards Track R. Tewari
ISSN: 2070-1721 IBM Almaden
C. Lever, Ed.
Oracle Corporation
March 2015 Administration Protocol for Federated File Systems
Abstract
This document describes the administration protocol for a federated
file system (FedFS) that enables file access and namespace traversal
across collections of independently administered fileservers. The
protocol specifies a set of interfaces by which fileservers with
different administrators can form a fileserver federation that
provides a namespace composed of the file systems physically hosted
on and exported by the constituent fileservers.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7533.

Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved.
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than English.

5.10.2. Description .......................................325.10.3. Errors ............................................336. Security Considerations ........................................337. IANA Considerations ............................................348. References .....................................................348.1. Normative References ......................................348.2. Informative References ....................................35
Acknowledgments ...................................................36
Authors' Addresses ................................................371. Introduction
A federated file system enables file access and namespace traversal
in a uniform, secure, and consistent manner across multiple
independent fileservers within an enterprise (and possibly across
multiple enterprises) with reasonably good performance.
Traditionally, building a namespace that spans multiple fileservers
has been difficult for two reasons. First, the fileservers that
export pieces of the namespace are often not in the same
administrative domain. Second, there is no standard mechanism for
the fileservers to cooperatively present the namespace. Fileservers
might provide proprietary management tools, and in some cases, an
administrator might be able to use the proprietary tools to build a
shared namespace out of the exported file systems. Relying on
vendor-proprietary tools does not work in larger enterprises or when
collaborating across enterprises because it is likely that the system
will contain fileservers running different software, each with their
own protocols, with no common protocol to manage the namespace or
exchange namespace information.
The requirements for federated namespaces are described in [RFC5716].
The protocol for federated file systems described in [RFC7532] allows
fileservers from different vendors and/or with different
administrators to cooperatively build a namespace.
This document describes the protocol used by administrators to
configure the fileservers and construct the namespace.
1.1. Definitions
Administrator: A user with the necessary authority to initiate
administrative tasks on one or more servers.
Admin Entity: A server or agent that administers a collection of
fileservers and persistently stores the namespace information.

File-Access Client: Standard off-the-shelf, network-attached storage
(NAS) client software that communicates with fileservers using a
standard file-access protocol.
Federation: A set of fileserver collections and singleton
fileservers that use a common set of interfaces and protocols in
order to provide to file-access clients a federated namespace
accessible through a file system access protocol.
Fileserver: A server that stores physical fileset data or refers
file-access clients to other fileservers. A fileserver provides
access to its shared file system data via a file-access protocol.
Fileset: The abstraction of a set of files and the directory tree
that contains them. A fileset is the fundamental unit of data
management in the federation.
Note that all files within a fileset are descendants of one
directory and that filesets do not span file systems.
File System: A self-contained unit of export for a fileserver and
the mechanism used to implement filesets. The fileset does not
need to be rooted at the root of the file system, nor at the
export point for the file system.
A single file system MAY implement more than one fileset, if the
file-access protocol and the fileserver permit this.
File-Access Protocol: A network file system access protocol such as
the Network File System (NFS) version 4 [RFC7530] or the Common
Internet File System (CIFS) [MS-SMB] [MS-SMB2] [MS-CIFS].
FSL (Fileset Location): The location of the implementation of a
fileset at a particular moment in time. An FSL MUST be something
that can be translated into a protocol-specific description of a
resource that a file-access client can access directly, such as an
fs_locations attribute (for NFSv4) or a share name (for CIFS).
FSN (Fileset Name): A platform-independent and globally unique name
for a fileset. Two FSLs that implement replicas of the same
fileset MUST have the same FSN, and if a fileset is migrated from
one location to another, the FSN of that fileset MUST remain the
same.
Junction: A file system object used to link a directory name in the
current fileset with an object within another fileset. The
server-side "link" from a leaf node in one fileset to the root of
another fileset.

Namespace: A filename/directory tree that a sufficiently authorized
file-access client can observe.
NSDB (Namespace Database) Service: A service that maps FSNs to FSLs.
The NSDB may also be used to store other information, such as
annotations for these mappings and their components.
NSDB Node: The name or location of a server that implements part of
the NSDB service and is responsible for keeping track of the FSLs
(and related information) that implement a given partition of the
FSNs.
Referral: A server response to a file-access client access that
directs the client to evaluate the current object as a reference
to an object at a different location (specified by an FSL) in
another fileset and possibly hosted on another fileserver. The
client re-attempts the access to the object at the new location.
Replica: A redundant implementation of a fileset. Each replica
shares the same FSN but has a different FSL.
Replicas may be used to increase availability or performance.
Updates to replicas of the same fileset MUST appear to occur in
the same order; therefore, each replica is self-consistent at any
moment.
We do not assume that updates to each replica occur
simultaneously. If a replica is offline or unreachable, the other
replicas may be updated.
Server Collection: A set of fileservers administered as a unit. A
server collection may be administered with vendor-specific
software.
The namespace provided by a server collection could be part of the
federated namespace.
Singleton Server: A server collection containing only one server; a
stand-alone fileserver.
1.2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].

2. Protocol
The Remote Procedure Call (RPC) protocol used to convey
administration operations is the Open Network Computing (ONC) RPC
protocol [RFC5531]. The data structures used for the parameters and
return values of these procedures are expressed in this document in
External Data Representation (XDR) [RFC4506].
The XDR definitions below are formatted to allow the reader to easily
extract them from the document. The reader can use the following
shell script to extract the definitions:
<CODE BEGINS>
#!/bin/sh
grep '^ *///' | sed 's?^ */// ??' | sed 's?^ *///$??'
<CODE ENDS>
If the above script is stored in a file called "extract.sh" and this
document is in a file called "spec.txt", then the reader can do:
<CODE BEGINS>
sh extract.sh < spec.txt > admin1.xdr
<CODE ENDS>
The effect of the script is to remove leading white space from each
line, plus a sentinel sequence of "///".
The protocol definition in XDR notation is shown below. We begin by
defining basic constants and structures used by the protocol. We
then present the procedures defined by the protocol.
<CODE BEGINS>
/// /*
/// * Copyright (c) 2015 IETF Trust and the persons identified
/// * as authors of the code. All rights reserved.
/// *
/// * The authors of the code are:
/// * J. Lentini, C. Everhart, D. Ellard, R. Tewari, and M. Naik.
/// *
/// * Redistribution and use in source and binary forms, with
/// * or without modification, are permitted provided that the
/// * following conditions are met:
/// *

FEDFS_ERR_BADCHAR: A UTF-8 string contains a character that is not
supported by the server in the context in which it being used.
FEDFS_ERR_BADNAME: A name string in a request consisted of valid
UTF-8 characters supported by the server, but the name is not
supported by the server as a valid name for the current operation.
FEDFS_ERR_NAMETOOLONG: Returned when the pathname in an operation
exceeds the server's implementation limit.
FEDFS_ERR_LOOP: Returned when too many symbolic links were
encountered in resolving pathname.
FEDFS_ERR_BADXDR: The server encountered an XDR decoding error while
processing an operation.
FEDFS_ERR_EXIST: The junction specified already exists.
FEDFS_ERR_INVAL: Invalid argument for an operation.
FEDFS_ERR_IO: A hard error occurred while processing the requested
operation.
FEDFS_ERR_NOSPC: The requested operation would have caused the
server's file system to exceed some limit (for example, if there
is a fixed number of junctions per fileset or per server).
FEDFS_ERR_NOTJUNCT: The caller specified a path that does not end in
a junction as the operand for an operation that requires the last
component of the path to be a junction.
FEDFS_ERR_NOTLOCAL: The caller specified a path that contains a
junction in any position other than the last component.
FEDFS_ERR_PERM: The operation was not allowed because the caller is
either not a privileged user or not the owner of an object that
would be modified by the operation.
FEDFS_ERR_ROFS: A modifying operation was attempted on a read-only
file system.
FEDFS_ERR_SVRFAULT: An unanticipated non-protocol error occurred on
the server.
FEDFS_ERR_NSDB_ROUTE: The fileserver was unable to find a route to
the NSDB.

FEDFS_ERR_NSDB_DOWN: The fileserver determined that the NSDB was
down.
FEDFS_ERR_NSDB_CONN: The fileserver was unable to establish a
connection with the NSDB.
FEDFS_ERR_NSDB_AUTH: The fileserver was unable to authenticate and
establish a secure connection with the NSDB.
FEDFS_ERR_NSDB_LDAP: A Lightweight Directory Access Protocol (LDAP)
error occurred on the connection between the fileserver and NSDB.
FEDFS_ERR_NSDB_LDAP_VAL: Indicates the same error as
FEDFS_ERR_NSDB_LDAP and allows the LDAP protocol error value to be
returned back to an ADMIN protocol client.
FEDFS_ERR_NSDB_NONCE: The fileserver was unable to locate the NSDB
Container Entry (NCE) in the appropriate NSDB.
FEDFS_ERR_NSDB_NOFSN: The fileserver was unable to locate the given
FSN in the appropriate NSDB.
FEDFS_ERR_NSDB_NOFSL: The fileserver was unable to locate any FSLs
for the given FSN in the appropriate NSDB.
FEDFS_ERR_NSDB_RESPONSE: The fileserver received a malformed
response from the NSDB. This includes situations when an NSDB
entry (e.g., FSN or FSL) is missing a required attribute.
FEDFS_ERR_NSDB_FAULT: An unanticipated error related to the NSDB
occurred.
FEDFS_ERR_NSDB_PARAMS: The fileserver does not have any connection
parameters on record for the specified NSDB.
FEDFS_ERR_NSDB_LDAP_REFERRAL: The fileserver received an LDAP
referral that it was unable to follow.
FEDFS_ERR_NSDB_LDAP_REFERRAL_VAL: Indicates the same error as
FEDFS_ERR_NSDB_LDAP_REFERRAL and allows the LDAP protocol error
value to be returned back to an ADMIN protocol client.
FEDFS_ERR_NSDB_LDAP_REFERRAL_NOTFOLLOWED: The fileserver received an
LDAP referral that it chose not to follow, either because the
fileserver does not support following LDAP referrals or LDAP
referral following is disabled.

FEDFS_ERR_NSDB_PARAMS_LDAP_REFERRAL: The fileserver received an LDAP
referral that it chose not to follow because the fileserver had no
NSDB parameters for the NSDB targeted by the LDAP referral.
FEDFS_ERR_PATH_TYPE_UNSUPP: The fileserver does not support the
specified FedFsPathType value.
FEDFS_ERR_NOTSUPP: The fileserver does not support the specified
procedure.
FEDFS_ERR_DELAY: The fileserver initiated the request but was not
able to complete it in a timely fashion. The ADMIN protocol
client should wait and then try the request with a new RPC
transaction ID.
FEDFS_ERR_NO_CACHE: The fileserver does not implement an FSN-to-FSL
cache.
FEDFS_ERR_UNKNOWN_CACHE: The software receiving the ONC RPC request
is unaware if the fileserver implements an FSN-to-FSL cache or is
unable to communicate with the FSN-to-FSL cache if it exists.
FEDFS_ERR_NO_CACHE_UPDATE: The fileserver was unable to update its
FSN-to-FSL cache.
4. Data Types
The basic data types defined above are formatted as follows:
FedFsUuid: A universally unique identifier (UUID) as described in
[RFC4122] as a version 4 UUID. The UUID MUST be formatted in
network byte order.
FedFsNsdbName: A (hostname, port) pair.
The hostname is a variable-length UTF-8 string that represents an
NSDB's network location in DNS name notation. It SHOULD be
prepared using the domain name rules defined in Section 12.6
("Types with Processing Defined by Other Internet Areas") of
[RFC7530]. The DNS name MUST be represented using a fully
qualified domain name.
The port value in the FedFsNsdbName indicates the LDAP port on the
NSDB (see [RFC4511]). The value MUST be in the range 0 to 65535.
A value of 0 indicates that the standard LDAP port number, 389,
MUST be assumed.

FSNs are immutable and invariant. The attributes of an FSN,
including the fedfsNsdbName, are expected to remain constant.
Therefore, a FedFsNsdbName MUST NOT contain a network address,
such as an IPv4 or IPv6 address, as this would indefinitely assign
the network address.
FedFsPathComponent: A case-sensitive UTF-8 string containing a file
system path component. The component names of an NFSv4 pathname
MUST be prepared using the component name rules defined in
Section 12 ("Internationalization") of [RFC7530] prior to encoding
the path component of an NFS URI.
FedFsPathName: A variable-length array of FedFsPathComponent values
representing a file system path. The path's first component is
stored at the first position of the array, the second component is
stored at the second position of the array, and so on.
The path "/" MUST be encoded as an array with zero components.
A FedFsPathName MUST NOT contain any zero-length components.
FedFsPath: A pathname container. The format and semantics of the
pathname are defined by the FedFsPathType value.
FedFsPathType: The type-specific description of a pathname.
A FEDFS_PATH_SYS is an implementation-dependent administrative
pathname. For example, it could be a local file system path.
A FEDFS_PATH_NFS is a pathname in the NFSv4 server's single-server
namespace.
FedFsNsdbParams: A set of parameters for connecting to an NSDB.
Conceptually, the fileserver contains a data structure that maps
an NSDB name (DNS name and port value) to these LDAP connection
parameters.
The secType field indicates the security mechanism that MUST be
used to protect all connections to the NSDB with the connection
parameters.
A value of FEDFS_SEC_NONE indicates that a transport security
mechanism MUST NOT be used when connecting to the NSDB. In this
case, the secData array will have a length of zero.
A value of FEDFS_SEC_TLS indicates that the StartTLS security
mechanism [RFC4513] MUST be used to protect all connections to the
NSDB. In this case, the secData array will contain an X.509v3

root certificate in binary DER format [RFC5280] fulfilling the
Transport Layer Security (TLS) requirement that root keys be
distributed independently from the TLS protocol. The certificate
MUST be used by the fileserver as a trust anchor to validate the
NSDB's TLS server certificate list chain (see Section 7.4.2 of
[RFC5246]) and thus authenticate the identity of the NSDB. The
certificate could be that of a certificate authority or a self-
signed certificate. To ensure that this security configuration
information does not cause vulnerabilities for other services,
trust anchors provided through secData MUST only be used for the
NSDB service (as opposed to being installed as system-wide trust
anchors for other services). Most popular TLS libraries provide
ways in which this can be done, such as denoting a private file
system location for the certificates.
4.1. FedFsNsdbName Equality
Two FedFsNsdbNames are considered equal if their respective hostname
and port fields contain the same values. The only exception to this
rule is that a value of 0 in the port field always matches the
standard LDAP port number, 389.
Therefore, the FedFsNsdbName "(nsdb.example.com, 0)" is considered
equal to "(nsdb.example.com, 389)" but not equal to
"(nsdb.example.com, 1066)" since the port numbers are different or
"(nsdb.foo.example.com, 389)" since the hostnames are different.
5. Procedures
The procedures defined in Section 2 are described in detail in the
following sections.
Fileservers that participate as "internal" nodes in the federated
namespace MUST implement the following procedures:
FEDFS_NULL
FEDFS_CREATE_JUNCTION
FEDFS_DELETE_JUNCTION
FEDFS_LOOKUP_JUNCTION
FEDFS_SET_NSDB_PARAMS
FEDFS_GET_NSDB_PARAMS
FEDFS_GET_LIMITED_NSDB_PARAMS
Furthermore, they SHOULD implement the following procedures:
FEDFS_CREATE_REPLICATION
FEDFS_DELETE_REPLICATION
FEDFS_LOOKUP_REPLICATION

Fileservers that participate as "leaf" nodes in the namespace (i.e.,
fileservers that host filesets that are the target of junctions but
that do not contain any junctions) are not required to implement any
of these operations.
Operations that modify the state of a replicated fileset MUST result
in the update of all of the replicas in a consistent manner.
Ideally, all of the replicas SHOULD be updated before any operation
returns. If one or more of the replicas are unavailable, the
operation MAY succeed, but the changes MUST be applied before the
unavailable replicas are brought back online. We assume that
replicas are updated via some protocol that permits state changes to
be reflected consistently across the set of replicas in such a manner
that the replicas will converge to a consistent state within a
bounded number of successful message exchanges between the servers
hosting the replicas.
5.1. FEDFS_NULL
5.1.1. Synopsis
The standard NULL procedure.
5.1.2. Description
The null RPC, which is included, by convention, in every ONC RPC
protocol. This procedure does not take any arguments and does not
produce a result.
5.1.3. Errors
None.
5.2. FEDFS_CREATE_JUNCTION
5.2.1. Synopsis
Create a new junction from some location on the server (defined as a
pathname) to an FSN.
5.2.2. Description
This operation creates a junction from a server-relative path to a
(potentially) remote fileset named by the given FSN.
The junction directory on the server is identified by a pathname in
the form of an array of one or more UTF-8 path component strings. It
is not required that this path be accessible in any other manner

(e.g., to a file-access client). This path does not appear in the
federated namespace, except by coincidence; there is no requirement
that the global namespace parallel the server namespace, nor is it
required that this path be relative to the server pseudo-root. It
does not need to be a path that is accessible via NFS (although the
junction will be of limited utility if the directory specified by the
path is not also accessible via NFS).
If the fileset is read-only, then this operation MUST indicate this
with a status of FEDFS_ERR_ROFS.
If the path contains a character that is not supported by the server,
then status FEDFS_ERR_BADCHAR MUST be returned.
The path is REQUIRED to exist and be completely local to the server.
It MUST NOT contain a junction. If the last component of the path is
a junction (i.e., this operation is attempting to create a junction
where one already exists), then this operation MUST return the error
FEDFS_ERR_EXIST (even if the requested junction is identical to the
current junction). If any other component of the path is a junction,
then this operation MUST fail with status FEDFS_ERR_NOTLOCAL. The
path might contain a symbolic link (if supported by the local
server), but the traversal of the path MUST remain within the server-
local namespace.
If any component of the path does not exist, then the operation MUST
fail with status FEDFS_ERR_INVAL.
The server MAY enforce the local permissions on the path, including
the final component. If a server wishes to report that a path cannot
be traversed because of insufficient permissions, or the final
component is an unexecutable or unwritable directory, then the
operation MUST fail with status FEDFS_ERR_ACCESS.
The operation SHOULD fail with status FEDFS_ERR_NSDB_PARAMS if the
fileserver does not have any connection parameters on record for the
specified NSDB, or the server may allow the operation to proceed
using some set of default NSDB connection parameters.
The association between the path and the FSN MUST be durable before
the operation returns successfully. If the operation return code
indicates success, then the junction was successfully created and is
immediately accessible.
If successful, subsequent references via NFSv4.0 [RFC7530] or NFSv4.1
[RFC5661] clients to the directory that has been replaced by the
junction will result in a referral to a current location of the
target fileset [RFC7532].

The effective permissions of the directory that is converted, by this
operation, into a junction are the permissions of the root directory
of the target fileset. The original permissions of the directory
(and any other attributes it might have) are subsumed by the
junction.
This operation does not create a fileset at the location targeted by
the junction. If the target fileset does not exist, the junction
will still be created. An NFS client will discover the missing
fileset when it traverses the junction.
5.2.3. Errors
FEDFS_ERR_ACCESS
FEDFS_ERR_BADCHAR
FEDFS_ERR_BADNAME
FEDFS_ERR_NAMETOOLONG
FEDFS_ERR_LOOP
FEDFS_ERR_BADXDR
FEDFS_ERR_EXIST
FEDFS_ERR_INVAL
FEDFS_ERR_IO
FEDFS_ERR_NOSPC
FEDFS_ERR_NOTLOCAL
FEDFS_ERR_PERM
FEDFS_ERR_ROFS
FEDFS_ERR_SVRFAULT
FEDFS_ERR_PATH_TYPE_UNSUPP
FEDFS_ERR_NOTSUPP
FEDFS_ERR_DELAY
5.3. FEDFS_DELETE_JUNCTION
5.3.1. Synopsis
Delete an existing junction from some location on the server (defined
as a pathname).
5.3.2. Description
This operation removes a junction specified by a server-relative
path.
As with FEDFS_CREATE_JUNCTION, the junction on the server is
identified by a pathname in the form of an array of one or more UTF-8
path component strings. It is not required that this path be
accessible in any other manner (e.g., to a file-access client). This
path does not appear in the federated namespace, except by

coincidence; there is no requirement that the global namespace
reflect the server namespace, nor is it required that this path be
relative to the server pseudo-root. It does not need to be a path
that is accessible via NFS.
If the fileset is read-only, then this operation MUST indicate this
with a status of FEDFS_ERR_ROFS.
If the path contains a character that is not supported by the server,
then status FEDFS_ERR_BADCHAR MUST be returned.
The path used to delete a junction might not be the same path that
was used to create the junction. If the namespace on the server has
changed, then the junction might now appear at a different path than
where it was created. If there is more than one valid path to the
junction, any of them can be used.
The path is REQUIRED to exist and be completely local to the server.
It MUST NOT contain a junction, except as the final component, which
MUST be a junction. If any other component of the path is a
junction, then this operation MUST fail with status
FEDFS_ERR_NOTLOCAL. If the last component of the path is not a
junction, then this operation MUST return status FEDFS_ERR_NOTJUNCT.
The path might contain a symbolic link (if supported by the local
server), but the traversal of the path MUST remain within the server-
local namespace.
The server MAY enforce the local permissions on the path, including
the final component. If a server wishes to report that a path cannot
be traversed because of insufficient permissions, or the final
component is an unexecutable or unwritable directory, then the
operation MUST fail with status FEDFS_ERR_ACCESS.
The removal of the association between the path and the FSN MUST be
durable before the operation returns successfully. If the operation
return code indicates success, then the junction was successfully
destroyed.
The effective permissions and other attributes of the directory that
is restored by this operation SHOULD be identical to their value
prior to the creation of the junction.
After removal of the junction, the fileserver MAY check if any of its
existing junctions reference the NSDB specified in the removed
junction's FSN. If the NSDB is not referenced, the fileserver MAY
delete the connection parameters of the unreferenced NSDB.

5.3.3. Errors
FEDFS_ERR_ACCESS
FEDFS_ERR_BADCHAR
FEDFS_ERR_BADNAME
FEDFS_ERR_NAMETOOLONG
FEDFS_ERR_LOOP
FEDFS_ERR_BADXDR
FEDFS_ERR_INVAL
FEDFS_ERR_IO
FEDFS_ERR_NOTJUNCT
FEDFS_ERR_NOTLOCAL
FEDFS_ERR_PERM
FEDFS_ERR_ROFS
FEDFS_ERR_SVRFAULT
FEDFS_ERR_PATH_TYPE_UNSUPP
FEDFS_ERR_NOTSUPP
FEDFS_ERR_DELAY
5.4. FEDFS_LOOKUP_JUNCTION
5.4.1. Synopsis
Query the server to discover the current value of the junction (if
any) at a given path in the server namespace.
5.4.2. Description
This operation queries a server to determine whether a given path
ends in a junction. If it does, the FSN to which the junction refers
and the fileserver's ability to resolve the junction is returned.
Ordinary NFSv4 operations do not provide any general mechanism to
determine whether an object is a junction -- there is no encoding
specified by the NFSv4 protocol that can represent this information.
As with FEDFS_CREATE_JUNCTION, the pathname MUST be in the form of an
array of one or more UTF-8 path component strings. It is not
required that this path be accessible in any other manner (e.g., to a
file-access client). This path does not appear in the federated
namespace, except by coincidence; there is no requirement that the
global namespace reflect the server namespace, nor is it required
that this path be relative to the server pseudo-root. It does not
need to be a path that is accessible via NFS.
If the path contains a character that is not supported by the server,
then status FEDFS_ERR_BADCHAR MUST be returned.

The path used to look up a junction might not be the same path that
was used to create the junction. If the namespace on the server has
changed, then a junction might now appear at a different path than
where it was created. If there is more than one valid path to the
junction, any of them might be used.
The path is REQUIRED to exist and be completely local to the server.
It MUST NOT contain a junction, except as the final component. If
any other component of the path is a junction, then this operation
MUST fail with status FEDFS_ERR_NOTLOCAL. If the last component of
the path is not a junction, then this operation MUST return the
status FEDFS_ERR_NOTJUNCT. The path might contain a symbolic link
(if supported by the local server), but the traversal of the path
MUST remain within the server-local namespace.
The server MAY enforce the local permissions on the path, including
the final component. If a server wishes to report that a path cannot
be traversed because of insufficient permissions, or the final
component is an unexecutable or unwritable directory, then the
operation MUST fail with status FEDFS_ERR_ACCESS.
If the junction exists, the resolve parameter allows for testing the
fileserver's ability to resolve the junction. If the junction does
not exist, the fileserver will ignore the resolve parameter.
If the junction exists and the resolve parameter is set to
FEDFS_RESOLVE_NONE, the fileserver MUST NOT attempt to resolve the
FSN. This will allow an administrator to obtain the junction's FSN
even if the resolution would fail. Therefore, on success, the result
of a FEDFS_RESOLVE_NONE call will return a zero-length fsl list in
the FedFsLookupResOk structure.
If the junction exists and the resolve parameter is set to
FEDFS_RESOLVE_CACHE, the fileserver MUST attempt to resolve the FSN
using its FSL cache, if one exists. The fileserver MUST NOT resolve
the FSN by contacting the appropriate NSDB. If the fileserver's
cache does not have a mapping for the FSN in question, the result of
the operation MUST be FEDFS_OK with 0 elements in the
FedFsLookupResOk structure's fsl array. The operation MAY fail with
status FEDFS_ERR_NO_CACHE if the fileserver does not contain an FSN-
to-FSL cache or with status FEDFS_ERR_UNKNOWN_CACHE if the state of
the cache is unknown.
If the junction exists and the resolve parameter is set to
FEDFS_RESOLVE_NSDB, the fileserver MUST attempt to resolve the FSN by
contacting the appropriate NSDB. The FSN MUST NOT be resolved using
cached information. The resolution MAY fail with
FEDFS_ERR_NSDB_ROUTE, FEDFS_ERR_NSDB_DOWN, FEDFS_ERR_NSDB_CONN,

FEDFS_ERR_NSDB_AUTH, FEDFS_ERR_NSDB_LDAP, FEDFS_ERR_NSDB_LDAP_VAL,
FEDFS_ERR_NSDB_NOFSN, FEDFS_ERR_NSDB_NOFSL, FEDFS_ERR_NSDB_NONCE,
FEDFS_ERR_NSDB_RESPONSE, FEDFS_ERR_NSDB_FAULT,
FEDFS_ERR_NSDB_LDAP_REFERRAL, FEDFS_ERR_NSDB_LDAP_REFERRAL_VAL,
FEDFS_ERR_NSDB_LDAP_REFERRAL_NOTFOLLOWED, or
FEDFS_ERR_NSDB_PARAMS_LDAP_REFERRAL, depending on the nature of the
failure.
In the case of an LDAP failure, the fileserver MUST return either
FEDFS_ERR_NSDB_LDAP or FEDFS_ERR_NSDB_LDAP_VAL. FEDFS_ERR_NSDB_LDAP
indicates that an LDAP protocol error occurred during the resolution.
FEDFS_ERR_NSDB_LDAP_VAL also indicates that an LDAP protocol error
occurred during the resolution and allows the LDAP protocol error
value to be returned in the FedFsLookupRes's ldapResultCode field
(see the resultCode values in Section 4.1.9 of [RFC4511]).
If the NSDB responds with an LDAP referral, either the Referral type
defined in Section 4.1.10 of [RFC4511] or the SearchResultReference
type defined in Section 4.5.3 of [RFC4511], the fileserver SHOULD
process the LDAP referral using the same policies as the fileserver's
file-access protocol server. The fileserver MUST indicate a failure
while processing the LDAP referral using
FEDFS_ERR_NSDB_LDAP_REFERRAL, FEDFS_ERR_NSDB_LDAP_REFERRAL_VAL,
FEDFS_ERR_NSDB_LDAP_REFERRAL_NOTFOLLOWED, or
FEDFS_ERR_NSDB_PARAMS_LDAP_REFERRAL. The
FEDFS_ERR_NSDB_LDAP_REFERRAL_VAL is analogous to the
FEDFS_ERR_NSDB_LDAP_VAL error and allows the LDAP protocol error
value to be returned in the FedFsLookupResReferralVal's
ldapResultCode field. The FEDFS_ERR_NSDB_LDAP_REFERRAL and
FEDFS_ERR_NSDB_PARAMS_LDAP_REFERRAL errors allow the NSDB targeted by
the LDAP referral to be returned in the FedFsLookupRes's targetNsdb
field. Similarly, the FEDFS_ERR_NSDB_LDAP_REFERRAL_VAL error
includes this information in the FedFsLookupResReferralVal's
targetNsdb.
If the fileserver has a cache of FSL records, the process of
resolving an FSN using an NSDB SHOULD result in the cache being
updated. A failure to update the cache MAY be indicated with the
FEDFS_ERR_NO_CACHE_UPDATE status value, or the operation may complete
successfully.
When updating the cache, new FSLs for the given FSN SHOULD be added
to the cache, and deleted FSLs SHOULD be removed from the cache.
This behavior is desirable because it allows an administrator to
proactively request that the fileserver refresh its FSL cache. For
example, an administrator might like to refresh the fileserver's
cache when changes are made to an FSN's FSLs.

5.5. FEDFS_CREATE_REPLICATION
5.5.1. Synopsis
Set an FSN representing the replication information for the fileset
containing the pathname.
5.5.2. Description
This operation indicates the replication information to be returned
for a particular fileset. An NFSv4 client might request fs_locations
or fs_locations_info at any time to detect other copies of this
fileset, and this operation supports this by supplying the FSN the
fileserver should use to respond. This FSN should be associated with
the entire fileset in which the path resides and should be used to
satisfy fs_locations or fs_locations_info attribute requests whenever
no junction is being accessed; if a junction is being accessed, the
FSN specified by FEDFS_CREATE_JUNCTION will take precedence. Setting
the replication FSN on a fileset that already has a replication FSN
set is allowed.
This operation differs from FEDFS_CREATE_JUNCTION in that it controls
a fileset-wide attribute not associated with a junction.
The server SHOULD permit this operation even on read-only filesets
but MUST return FEDFS_ERR_ROFS if this is not possible.
If the path contains a character that is not supported by the server,
then status FEDFS_ERR_BADCHAR MUST be returned.
The path is REQUIRED to exist and be completely local to the server.
It MUST NOT contain a junction. If any component of the path is a
junction, then this operation MUST fail with status
FEDFS_ERR_NOTLOCAL. The path might contain a symbolic link (if
supported by the local server), but the traversal of the path MUST
remain within the server-local namespace.
The server MAY enforce the local permissions on the path, including
the final component. If a server wishes to report that a path cannot
be traversed because of insufficient permissions, or the final
component is an unexecutable or unwritable directory, then the
operation MUST fail with status FEDFS_ERR_ACCESS.
The operation SHOULD fail with status FEDFS_ERR_NSDB_PARAMS if the
fileserver does not have any connection parameters on record for the
specified NSDB, or the server may allow the operation to proceed
using some set of default NSDB connection parameters.

The same FSN value SHOULD be associated with all replicas of a file
system. Depending on the underlying representation, the FSN
associated with a file system might or might not be replicated
automatically with the file system replication mechanism. Therefore,
if FEDFS_CREATE_REPLICATION is used on one replica of a file system,
it SHOULD be used on all replicas.
5.5.3. Errors
FEDFS_ERR_ACCESS
FEDFS_ERR_BADCHAR
FEDFS_ERR_BADNAME
FEDFS_ERR_NAMETOOLONG
FEDFS_ERR_LOOP
FEDFS_ERR_BADXDR
FEDFS_ERR_EXIST
FEDFS_ERR_INVAL
FEDFS_ERR_IO
FEDFS_ERR_NOSPC
FEDFS_ERR_NOTLOCAL
FEDFS_ERR_PERM
FEDFS_ERR_ROFS
FEDFS_ERR_SVRFAULT
FEDFS_ERR_PATH_TYPE_UNSUPP
FEDFS_ERR_NOTSUPP
FEDFS_ERR_DELAY
5.6. FEDFS_DELETE_REPLICATION
5.6.1. Synopsis
Remove the replication information for the fileset containing the
pathname.
5.6.2. Description
This operation removes any replication information from the fileset
in which the path resides, such that NFSv4 client requests for
fs_locations or fs_locations_info in the absence of a junction will
not be satisfied.
This operation differs from FEDFS_DELETE_JUNCTION in that it controls
a fileset-wide attribute not associated with a junction.
The server SHOULD permit this operation even on read-only filesets
but MUST return FEDFS_ERR_ROFS if this is not possible.

If the path contains a character that is not supported by the server,
then status FEDFS_ERR_BADCHAR MUST be returned.
The path is REQUIRED to exist and be completely local to the server.
It MUST NOT contain a junction. If any component of the path is a
junction, then this operation MUST fail with status
FEDFS_ERR_NOTLOCAL.
The server MAY enforce the local permissions on the path, including
the final component. If a server wishes to report that a path cannot
be traversed because of insufficient permissions, or the final
component is an unexecutable or unwritable directory, then the
operation MUST fail with status FEDFS_ERR_ACCESS.
5.6.3. Errors
FEDFS_ERR_ACCESS
FEDFS_ERR_BADCHAR
FEDFS_ERR_BADNAME
FEDFS_ERR_NAMETOOLONG
FEDFS_ERR_LOOP
FEDFS_ERR_BADXDR
FEDFS_ERR_INVAL
FEDFS_ERR_IO
FEDFS_ERR_NOTJUNCT
FEDFS_ERR_NOTLOCAL
FEDFS_ERR_PERM
FEDFS_ERR_ROFS
FEDFS_ERR_SVRFAULT
FEDFS_ERR_PATH_TYPE_UNSUPP
FEDFS_ERR_NOTSUPP
FEDFS_ERR_DELAY
5.7. FEDFS_LOOKUP_REPLICATION
5.7.1. Synopsis
Query the server to discover the current replication information (if
any) at the given path.
5.7.2. Description
This operation queries a server to determine whether a fileset
containing the given path has replication information associated with
it. If it does, the FSN for that replication information is
returned.

This operation differs from FEDFS_LOOKUP_JUNCTION in that it inquires
about a fileset-wide attribute not associated with a junction.
If the path contains a character that is not supported by the server,
then status FEDFS_ERR_BADCHAR MUST be returned.
The path is REQUIRED to exist and be completely local to the server.
It MUST NOT contain a junction. If any component of the path is a
junction, then this operation MUST fail with status
FEDFS_ERR_NOTLOCAL.
The server MAY enforce the local permissions on the path, including
the final component. If a server wishes to report that a path cannot
be traversed because of insufficient permissions, or the final
component is an unexecutable or unwritable directory, then the
operation MUST fail with status FEDFS_ERR_ACCESS.
Interpretation of the resolve parameter and the procedure's results
shall be the same as specified in Section 5.4 for the
FEDFS_LOOKUP_JUNCTION operation.
5.7.3. Errors
FEDFS_ERR_ACCESS
FEDFS_ERR_BADCHAR
FEDFS_ERR_BADNAME
FEDFS_ERR_NAMETOOLONG
FEDFS_ERR_LOOP
FEDFS_ERR_BADXDR
FEDFS_ERR_INVAL
FEDFS_ERR_IO
FEDFS_ERR_NOTJUNCT
FEDFS_ERR_NOTLOCAL
FEDFS_ERR_PERM
FEDFS_ERR_SVRFAULT
FEDFS_ERR_NSDB_ROUTE
FEDFS_ERR_NSDB_DOWN
FEDFS_ERR_NSDB_CONN
FEDFS_ERR_NSDB_AUTH
FEDFS_ERR_NSDB_LDAP
FEDFS_ERR_NSDB_LDAP_VAL
FEDFS_ERR_NSDB_NONCE
FEDFS_ERR_NSDB_NOFSN
FEDFS_ERR_NSDB_NOFSL
FEDFS_ERR_NSDB_RESPONSE
FEDFS_ERR_NSDB_FAULT
FEDFS_ERR_NSDB_PARAMS
FEDFS_ERR_NSDB_LDAP_REFERRAL

FEDFS_ERR_NSDB_LDAP_REFERRAL_VAL
FEDFS_ERR_NSDB_LDAP_REFERRAL_NOTFOLLOWED
FEDFS_ERR_NSDB_PARAMS_LDAP_REFERRAL
FEDFS_ERR_PATH_TYPE_UNSUPP
FEDFS_ERR_NOTSUPP
FEDFS_ERR_DELAY
FEDFS_ERR_NO_CACHE
FEDFS_ERR_UNKNOWN_CACHE
5.8. FEDFS_SET_NSDB_PARAMS
5.8.1. Synopsis
Set the connection parameters for the specified NSDB.
5.8.2. Description
This operation allows an administrator to set the connection
parameters for a given NSDB.
If a record for the given NSDB does not exist, a new record is
created with the specified connection parameters.
If a record for the given NSDB does exist, the existing connection
parameters are replaced with the specified connection parameters.
An NSDB is specified using a FedFsNsdbName. The rules in Section 4.1
define when two FedFsNsdbNames are considered equal.
The given NSDB need not be referenced by any junctions on the
fileserver. This situation will occur when connection parameters for
a new NSDB are installed.
The format of the connection parameters is described in Section 4.
On success, this operation returns FEDFS_OK. When the operation
returns, the new connection parameters SHOULD be used for all
subsequent LDAP connections to the given NSDB. Existing connections
MAY be terminated and re-established using the new connection
parameters. The connection parameters SHOULD be durable across
fileserver reboots.
On failure, an error value indicating the type of error is returned.
If the operation's associated user does not have sufficient
permissions to create/modify NSDB connection parameters, the
operation MUST return FEDFS_ERR_ACCESS.

5.8.3. Errors
FEDFS_ERR_ACCESS
FEDFS_ERR_BADCHAR
FEDFS_ERR_BADNAME
FEDFS_ERR_BADXDR
FEDFS_ERR_INVAL
FEDFS_ERR_IO
FEDFS_ERR_NOSPC
FEDFS_ERR_SVRFAULT
FEDFS_ERR_NOTSUPP
FEDFS_ERR_DELAY
5.9. FEDFS_GET_NSDB_PARAMS
5.9.1. Synopsis
Get the connection parameters for the specified NSDB.
5.9.2. Description
This operations allows an administrator to retrieve connection
parameters, if they exist, for the given NSDB.
An NSDB is specified using a FedFsNsdbName. The rules in Section 4.1
define when two FedFsNsdbNames are considered equal.
A set of connection parameters is considered a match if their
associated NSDB is equal (as defined in Section 4.1) to the
operation's NSDB argument. Therefore, there is at most one set of
connection parameters that can match the query described by this
operation.
The format of the connection parameters is described in Section 4.
On success, this operation returns FEDFS_OK and the connection
parameters on record for the given NSDB.
On failure, an error value indicating the type of error is returned.
This operation MUST return FEDFS_ERR_NSDB_PARAMS to indicate that
there are no connection parameters on record for the given NSDB. If
the operation's associated user does not have sufficient permissions
to view NSDB connection parameters, the operation MUST return
FEDFS_ERR_ACCESS.

5.9.3. Errors
FEDFS_ERR_ACCESS
FEDFS_ERR_BADCHAR
FEDFS_ERR_BADNAME
FEDFS_ERR_BADXDR
FEDFS_ERR_INVAL
FEDFS_ERR_IO
FEDFS_ERR_SVRFAULT
FEDFS_ERR_NSDB_PARAMS
FEDFS_ERR_NOTSUPP
FEDFS_ERR_DELAY
5.10. FEDFS_GET_LIMITED_NSDB_PARAMS
5.10.1. Synopsis
Get a limited subset of the connection parameters for the specified
NSDB.
5.10.2. Description
This operation allows an administrator to retrieve a limited subset
of information on the connection parameters, if they exist, for the
given NSDB.
An NSDB is specified using a FedFsNsdbName. The rules in Section 4.1
define when two FedFsNsdbNames are considered equal.
A set of connection parameters is considered a match if their
associated NSDB is equal (as defined in Section 4.1) to the
operation's NSDB argument. Therefore, there is at most one set of
connection parameters that can match the query described by this
operation.
This operation returns a limited subset of the connection parameters.
Only the FedFsConnectionSec mechanism that is used to protect
communication between the fileserver and NSDB is returned.
Viewing the limited subset of NSDB connection parameters returned by
FEDFS_GET_LIMITED_NSDB_PARAMS MAY be a less privileged operation than
viewing the entire set of NSDB connection parameters returned by
FEDFS_GET_NSDB_PARAMS. For example, the full contents of an NSDB's
connection parameters could contain sensitive information for some
security mechanisms. FEDFS_GET_LIMITED_NSDB_PARAMS allows the
fileserver to communicate a subset of the connection parameters (the
security mechanism) to users with sufficient permissions without
revealing more sensitive information.

On success, this operation returns FEDFS_OK and the
FedFsConnectionSec value on record for the given NSDB.
On failure, an error value indicating the type of error is returned.
This operation MUST return FEDFS_ERR_NSDB_PARAMS to indicate that
there are no connection parameters on record for the given NSDB. If
the operation's associated user does not have sufficient permissions
to view the subset of NSDB connection parameters returned by this
procedure, the operation MUST return FEDFS_ERR_ACCESS.
5.10.3. Errors
FEDFS_ERR_ACCESS
FEDFS_ERR_BADCHAR
FEDFS_ERR_BADNAME
FEDFS_ERR_BADXDR
FEDFS_ERR_INVAL
FEDFS_ERR_IO
FEDFS_ERR_SVRFAULT
FEDFS_ERR_NSDB_PARAMS
FEDFS_ERR_NOTSUPP
FEDFS_ERR_DELAY
6. Security Considerations
The security considerations of [RFC5531] apply to the protocol
described in this document. The ONC RPC protocol supports
authentication, integrity, and privacy via the RPCSEC_GSS framework
[RFC2203]. Fileservers that support the FedFS administration
protocol described in this document MUST support RPCSEC_GSS.
As with NFSv4.1 (see Section 2.2.1.1.1.1 of [RFC5661]), FedFS
administration protocol clients and servers MUST support RPCSEC_GSS's
integrity and authentication services. FedFS administration protocol
servers MUST support RPCSEC_GSS's privacy service. FedFS
administration protocol clients SHOULD support RPCSEC_GSS's privacy
service. When RPCSEC_GSS is employed on behalf of the FedFS
administration protocol, RPCSEC_GSS data integrity SHOULD be used.
It is strongly RECOMMENDED that an Access Control Service be employed
to restrict access to a fileserver's FedFS administration
configuration data via the FedFS administrative protocol to prevent
FedFS namespace corruption and protect NSDB communication parameters.
For example, when the FedFsNsdbParams secType field value
FEDFS_SEC_TLS is chosen, the payload is used to provision the trust
anchor root certificate for TLS secure communication between the

Acknowledgments
Daniel Ellard contributed significant parts of this document.
The authors and editor would like to thank Craig Everhart and Manoj
Naik, who were co-authors of an earlier draft version of this
document. In addition, we would like to thank Paul Lemahieu, Mario
Wurzl, and Robert Thurlow for helping to author this document.
We would like to thank Trond Myklebust for suggesting improvements to
the FSL pathname format, David Noveck for his suggestions on
internationalization and path encoding rules, and Nicolas Williams
for his suggestions.
The editor gratefully acknowledges the IESG reviewers, whose
constructive comments helped make this a much stronger document.
Finally, we would like to thank Andy Adamson, Rob Thurlow, and Tom
Haynes for helping to get this document out the door.
The extract.sh shell script and formatting conventions were first
described by the authors of the NFSv4.1 XDR specification [RFC5662].